file descriptors

pipes

1 files changed, 92 insertions, 1 deletions

diff --git a/syscall.c b/syscall.c
index 1d2eb54..c27c226 100644
--- a/syscall.c
+++ b/syscall.c
@@ -43,6 +43,88 @@ fetcharg(int argno, int *ip)
 }
 
 int
+putint(struct proc *p, unsigned addr, int ip)
+{
+  if(addr > p->sz - 4)
+    return 0;
+  memcpy(p->mem + addr, &ip, 4);
+  return 1;
+}
+
+int
+sys_pipe()
+{
+  struct fd *rfd = 0, *wfd = 0;
+  int f1 = -1, f2 = -1;
+  struct proc *p = curproc[cpu()];
+  unsigned fdp;
+
+  if(pipe_alloc(&rfd, &wfd) < 0)
+    goto oops;
+  if((f1 = fd_ualloc()) < 0)
+    goto oops;
+  p->fds[f1] = rfd;
+  if((f2 = fd_ualloc()) < 0)
+    goto oops;
+  p->fds[f2] = wfd;
+  if(fetcharg(0, &fdp) < 0)
+    goto oops;
+  if(putint(p, fdp, f1) < 0)
+    goto oops;
+  if(putint(p, fdp+4, f2) < 0)
+    goto oops;
+  return 0;
+
+ oops:
+  cprintf("sys_pipe failed\n");
+  if(rfd)
+    fd_close(rfd);
+  if(wfd)
+    fd_close(wfd);
+  if(f1 >= 0)
+    p->fds[f1] = 0;
+  if(f2 >= 0)
+    p->fds[f2] = 0;
+  return -1;
+}
+
+int
+sys_write()
+{
+  int fd, n;
+  unsigned addr;
+  struct proc *p = curproc[cpu()];
+
+  if(fetcharg(0, &fd) < 0 || fetcharg(1, &addr) < 0 || fetcharg(2, &n) < 0)
+    return -1;
+  if(fd < 0 || fd >= NOFILE)
+    return -1;
+  if(p->fds[fd] == 0)
+    return -1;
+  if(addr + n > p->sz)
+    return -1;
+  return fd_write(p->fds[fd], p->mem + addr, n);
+}
+
+int
+sys_read()
+{
+  int fd, n;
+  unsigned addr;
+  struct proc *p = curproc[cpu()];
+
+  if(fetcharg(0, &fd) < 0 || fetcharg(1, &addr) < 0 || fetcharg(2, &n) < 0)
+    return -1;
+  if(fd < 0 || fd >= NOFILE)
+    return -1;
+  if(p->fds[fd] == 0)
+    return -1;
+  if(addr + n > p->sz)
+    return -1;
+  return fd_read(p->fds[fd], p->mem + addr, n);
+}
+
+int
 sys_fork()
 {
   struct proc *np;
@@ -122,7 +204,7 @@ syscall()
   int num = cp->tf->tf_regs.reg_eax;
   int ret = -1;
 
-  cprintf("%x sys %d\n", cp, num);
+  //cprintf("%x sys %d\n", cp, num);
   switch(num){
   case SYS_fork:
     ret = sys_fork();
@@ -136,6 +218,15 @@ syscall()
   case SYS_cons_putc:
     ret = sys_cons_putc();
     break;
+  case SYS_pipe:
+    ret = sys_pipe();
+    break;
+  case SYS_write:
+    ret = sys_write();
+    break;
+  case SYS_read:
+    ret = sys_read();
+    break;
   default:
     cprintf("unknown sys call %d\n", num);
     // XXX fault